1. Technical Field of the Invention
The present invention relates to a device for collecting and separating a waste material containing oil and grease from an aqueous solution. More particularly, it relates to a compact, self-contained skimming device for removing oil and grease from an aqueous cleaning solution used in parts washers.
2. Description of Related Art
Industrial machinery parts washers utilize high pressure sprays of either solvent or aqueous cleaning solution to remove oil, grease, debris and sediment from the machinery parts. Users may either dispose of or filter and recycle the resulting waste cleaning solution. Disposal of the solution without recycling is costly and impractical. Regulators often classify such a solution that is contaminated with oil as a hazardous waste. Such a classification raises environmental concerns and increases the cost of disposal. If the user filters the recycled solution, the filters can clog up quickly and must be replaced frequently, which is also costly and impractical. The problem is further exacerbated if the waste cleaning solution contains large amounts of oil and grease. Oil and grease that accumulate in a washer system can cause operating problems such as cleaning difficulties, machine down-time, greater equipment wear, contamination of the cleaning solution, and possible bacteria growth in the oil and grease accumulated in the system.
Oil-water separators are available to extract oil and other lightweight pollutants from water. Power-spray parts washers utilize such devices, in conjunction with filters to remove debris, to recycle aqueous cleaning solutions. Industrial processes employ some devices to purify contaminated water before returning the water to the environment. Other devices skim oil off of the top of oil-water mixtures from the output of oil refinery storm sewer systems. Still other devices separate lubricating oil from aqueous coolant used in machining operations.
Large gravity separators and extractors separate oil from aqueous solutions by using either portable or centralized pumping systems. Such systems require user training, large amounts of power, and labor to operate. They occupy significant amounts of space and are expensive to purchase.
Designers have developed numerous small unattended oil removal devices, including belt, drum, and disk oil collection or skimming devices. However, each such device has disadvantages. Belt devices remove large amounts of water together with the oil and grease. The belt material also may be adversely affected by the heat of the wash water or the chemical composition of the cleaning solution. Drum devices occupy a large amount of space. They also remove a large quantity of water together with the oil and grease. Current disk skimmers also tend to remove much of the water together with the oil and grease. They employ multiple tanks, are heavy and bulky, and occupy a sizable area. Current designs utilize numerous components and require many manufacturing steps and user assembly. They require a second, secondary process step or a separate module for the separation of the oil and grease from the water. Some utilize screens to separate granules of loose debris from the oil and grease.